Multiple choice

The first heart sound 'lubb' is produced by

  1. the closure of AV-valve at the beginning of auricular systole

  2. the closure of AV-valve at the beginning of ventricular systole

  3. the closure of AV-valve at the beginning of ventricular diastole

  4. the closure of AV-valve at the beginning of auricular diastole

  5. both the auricles and ventricles are in relaxed or diastolic phase
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This answer is correct. The closure of AV-valve at the beginning of ventricular systole produces a sound “lubb” and is known as the first heart sound.

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